Indian Journal of Science and Technology

Abstract

The lubricants are most important component of any moving machinery system which helps to reduce the friction and thus overall wear and tear. Objectives: The important viscoelastic properties such as shear rate, shear stress, viscosity, Torque etc. of additivated mineral oil was investigated using a Rheometer and ultrasonic velocity measurements were conducted using nano fluid interferometer. Method: In the current experimental work, Multi Walled Carbon Nanotubes (MWCNT) were coated with stearic acid (carboxylic group) in order to investigate their viscoelastic properties as wear reduction additive for a mineral base engine oil (SAE 20W50). The functional MWCNTs were examined by FTIR technique, Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM). The MWCNTs were then dispersed in a mineral oil by ultrasonication. Findings: The results show that by functionalization of MWCNTs, the viscoelastic properties of the base mineral oil improved as more stable bonds were created on metallic surface due to improved absorption qualities. It was also deduced that due to coating of MWCNTs with carboxylic group stearic acid, the stability of suspension is high and it does not coagulate even after few months. Applications: The improved additivated engine oil finds applications in almost all major automobile uses and to reduce the harmful effect on the environment. 

Keywords: Carbon Nano-Tubes, Rheology, Viscoelasticity